Antisense technologies have been employed primarily to block gene expression. During the process of gene expression, the information encoded in a gene (DNA) is first transcribed into a messenger RNA (mRNA) that is in turn translated into a protein. The original idea behind antisense technology was to create a piece of polynucleotide (RNA or DNA) with a base sequence complementary to that of a particular messenger RNA. This antisense RNA would bind to the mRNA, preventing it from being translated into protein as shown below:
SENSE ANTISENSE 5'-ACGGTACGTAA-3' (SEQ ID NO:39) 5'-ttacgtaccgt-3' (SEQ ID NO:40) DNA .vertline..vertline..vertline..vertline..vertline..vertline..ve rtline..vertline..vertline..vertline..vertline. .vertline..vertline..vertline..vertline..vertline..vertline..vertline..ver tline..vertline..vertline..vertline. 3'-tgccatgcatt-5' 3'-AATGCATGGCA-5' .vertline. .vertline. .vertline. .vertline. v v RNA: 5'-ACGGUACGUAA-3' (SEQ ID NO:41) 5'-uuacguaccgu-3' (SEQ ID NO:42) .backslash. / .backslash. / .backslash. / .backslash. / .backslash. / .backslash. / SENSE --&gt; 5'ACGGUACGUAA-3' (SEQ ID NO:41) COMPLEX: .vertline..vertline..vertline..vertline.. vertline..vertline..vertline..vertline..vertline..vertline..vertline. 3'ugccaugcauu-5' &lt;-- ANTISENSE .vertline. (SEQ ID NO:42) X .vertline. v (PROTEIN)